Inkjet Ink Pigment Polymer Modification Wet Smudge
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Solution Overview
Problem
Pigment-based inkjet inks struggle to produce durable images on porous print media due to low resistance to wet smudge and increased viscosity when using polymeric additives, which also decrease optical density and printability.
Innovation Solution
An inkjet ink formulation featuring a modified pigment with a polymer of molecular weight equal to or greater than 4000 attached to the pigment surface, combined with a free binder and a fixer fluid, which enhances wet smudge resistance without compromising optical density or printability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric additives are used to improve wet smudge resistance, then wet smudge resistance is improved, but viscosity increases and printability decreases
Solution Approach 1:
The patent applies parameter changes by specifying a molecular weight threshold (≥4000) for the polymer attached to the pigment surface. This parameter change optimizes the balance between wet smudge resistance and viscosity, allowing the ink to maintain both durability and printability that were previously contradictory.
Solution Approach 2:
The patent creates a composite structure by attaching polymer chains to the pigment surface, forming a modified pigment that combines the properties of both the pigment (for color and durability) and the polymer (for wet smudge resistance). This composite approach allows achieving both improved wet smudge resistance and acceptable printability without the negative effects of adding separate polymeric additives.
2Reliability
If polymeric additives are used to improve wet smudge resistance, then wet smudge resistance is improved, but optical density decreases
Solution Approach 1:
By integrating the polymer directly onto the pigment surface to create a modified pigment, the patent avoids the need for separate polymeric additives that would compromise optical density. The composite structure ensures that the pigment maintains its color strength while the attached polymer provides wet smudge resistance.
Solution Approach 2:
The patent specifies that the polymer attached to the pigment surface should have a molecular weight of 4000 or greater. This parameter change ensures sufficient wet smudge resistance while maintaining optical density, as the polymer is covalently bonded to the pigment and does not interfere with light absorption.
3Stability of the object's composition
If dispersing agents are added to disperse pigment, then pigment dispersibility is improved, but viscosity increases
Solution Approach 1:
The patent creates a composite material by attaching polymer chains directly to the pigment surface, forming a modified pigment. This approach improves pigment dispersibility through the polymer's steric and/or electrostatic stabilization effects without requiring additional dispersing agents that would increase viscosity and affect printability.
Solution Approach 2:
The patent extracts the dispersing function from separate dispersing agents and integrates it directly into the pigment structure through polymer attachment. This eliminates the need for additional dispersing agents in the ink formulation, thereby avoiding the viscosity increase that would compromise printability.
4Stability of the object's composition
If small molecules are attached to pigment surface, then dispersibility is improved, but wet smudge resistance decreases
Solution Approach 1:
The patent applies parameter changes by specifying that the polymer attached to the pigment surface must have a molecular weight of 4000 or greater. This parameter change ensures that the attached polymer provides sufficient wet smudge resistance while maintaining good dispersibility, resolving the contradiction between using small molecules for dispersibility and needing large molecules for wet smudge resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides improved resistance to wet smudge and maintains optical density, while ensuring fast drying and low viscosity, resulting in durable and high-quality printed images on porous media.
Implementation Method 1
surfactants have been adsorbed or coated onto the pigment to improve dispersibility
Data Source
AI summary
A printing system for use in inkjet printing. The printing system includes an inkjet ink having a free binder, an additional free binder, and a chemically modified pigment, a fixer fluid and a porous print medium.